Obviously this is going to depend on the person. I think that depends on if the person goes into the social sciences with an open mind (yes, probably), seeking to uncover unknowing biases in their thinking (yes), or very set in their views (maybe?). I can't give you any data on the subject, and such data would be quite difficult to collect systematically and accurately, but I’ll tell you a little about how studying sociology and anthropology affected me personally (as well-meaning but fairly ignorant white liberal girl).

Studying sociology has helped me to deconstruct a lot of cultural baggage. Learning how and why racist/classist/sexist ideologies exist, who benefits from them, learning about not just individual bigotry but structural violence (the many ways the structure of society results in harm and discrimination against various groups), how the same people have been discriminated against throughout history, and each time period there has been a different iteration of it, learning about implicit bias - all of that has had a profound effect on my ideas. I uncovered prejudices that I did not know were prejudices and learned to think more broadly about these issues.

I developed a greater sense of personal responsibility, realizing that everyday things I say and do could contribute to societal racism/classism/sexism or combat it on a micro level. It’s not that I think that I’m going to change society with my small actions but at least I can try not to participate in the shitty parts. I avoid saying things that are sexist/racist/classist not because they would give offense/I should be politically correct, but because saying those things hurts people by reinforcing viewpoints that lead to discrimination and also may make it harder for some people to connect with me.

Learning about intersection also gave me a lot more depth of understanding of my own privilege, and added nuance to my thinking, which was previously well-meaning but not as productive or applicable to the realities people live with. From anthropology I learned to approach different cultures, including local ones, with humility. I must assume I do not understand them (because I really can’t if I am not part of them), and allow those in the culture to fill me in even on aspects that I might think are very obvious. This attitude is difficult to maintain and I do slip up often, but striving for it is now one of my most essential values. It helps to not pass judgment about behaviors in different groups that at a passing glance from my perspective look wrong, but often when looked at more closely are much more understandable, and that absolutely has made me a less prejudiced person.